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Where to mail your Idaho state tax return

Mail your Idaho Form 40 to Idaho State Tax Commission, PO Box 56, Boise, ID 83756-0056. Sign and date the form before mailing it.

Return (with or without payment)

Idaho State Tax Commission
PO Box 56
Boise, ID  83756-0056

Use this address for a paper Form 40 where return (with or without payment).

Verified September 2026tax.idaho.gov

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Type your letter in the browser. We print it, stamp it, and hand it to USPS — usually same business day. No printer, no stamps, no post office.

Mail my Idaho tax return — $5

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  • You write & pay
  • We print & envelope
  • USPS, next business day
  • Confirmation of Mailing emailed

Your name
Your return address

Idaho State Tax CommissionPO Box 56Boise, ID 83756-0056

Your letter, printed and mailed for you.

Key facts

  • Idaho uses one address for Form 40 regardless of whether you owe or are due a refund.
  • Make checks or money orders payable to the "Idaho State Tax Commission".
  • Idaho uses the same address whether or not you enclose a payment — attach Form ID-VP if you owe.
  • A mailed return is generally considered filed on time if it is postmarked by the state filing deadline — sign and date it, since an unsigned return isn't considered filed.
  • PostPal prints your return and hands it to USPS the next business day for $5 — no printer, envelope, or trip to the post office.

How to send your letter

  1. 1

    Confirm the address

    Idaho uses a single mailing address for Form 40, shown above, regardless of whether you're enclosing a payment.

  2. 2

    Assemble and sign your return

    Attach any required schedules and withholding statements to your Form 40. Sign and date it — an unsigned paper return isn't considered filed.

  3. 3

    Address the envelope exactly

    Use Idaho State Tax Commission at the address for your situation, shown above. Idaho uses the same address whether or not you enclose a payment — attach Form ID-VP if you owe.

  4. 4

    Mail it before the deadline

    A USPS postmark by the filing deadline counts as on time. Upload your return to PostPal and we print, envelope, and mail it within one business day for $5, with a dated confirmation emailed to you.

Common questions

Where do I mail my Idaho state tax return?

Mail it to Idaho State Tax Commission, PO Box 56, Boise, ID 83756-0056 — Idaho uses this one address regardless of whether you owe or are due a refund.

Does it matter which Idaho address I use?

No — Idaho doesn't split this by payment status, so there's only one address to use.

What do I make my check payable to?

The "Idaho State Tax Commission". Write your Social Security number and the tax year on the check or money order.

Is a mailed Idaho return considered on time if it's postmarked by the deadline?

Generally yes — most states, including Idaho, treat a return as timely filed if it carries a USPS postmark on or before the filing deadline. Keep proof of mailing for your records; PostPal emails you a dated confirmation.

Can PostPal mail my Idaho tax return for me?

Yes. Upload your completed, signed Form 40 and PostPal prints it and mails it to Idaho State Tax Commission, PO Box 56, Boise, ID 83756-0056 (or your correct address, based on your situation) the next business day for $5, with a dated Confirmation of Mailing.

Sources

Addresses verified September 2026 against official sources. Always confirm on the official site before time-sensitive filings.

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